In today's aeronautical datalink environment, aircraft datalink service is limited to communication links provided by datalink service providers. Large airlines can spend upwards of $10 million per year on datalink services. Datalink costs could be significantly reduced if aircraft had a means to communicate with the airline operations center without using datalink service providers. Given the large number of aircraft operating at any given time, a feasible approach is to form an ad-hoc network of aircraft where messages are relayed to the final destination. Establishing an ad-hoc network relies on two basic techniques: neighbor discovery and topology discovery. The purpose of neighbor discovery is to determine what nodes are within direct communication range. In mobile ad-hoc networks, neighbor relationships change frequently. Neighbor discovery is typically performed using a hello protocol over the communications network. To account for the continuously changing network topology, nodes broadcast hello messages periodically. Based on received hello messages, each node is able to ascertain its neighbor nodes. Before a routing decision can be made, a node must also determine a complete path to the destination. Topology discovery is performed to determine all the communication paths that are available in the network. During topology discovery, neighbor information is distributed to the entire network using topology control messages. The topology control messages are periodically distributed to the entire network using methods such as message flooding. The broadcast of hello messages and distribution of topology information introduces a significant amount of overhead to the network. Due to the overhead associated with neighbor discovery and topology discovery, establishing ad-hoc network routes and determining that an aircraft (node) in the route is no longer available, can cause considerable overhead in a communications network as well as delays in routing a message, or even result in dropped messages that cannot be delivered.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an ad-hoc air to air networking communication system that is efficient, reliable and relatively inexpensive to operate.